I don’t find it particularly offensive or disrespectful. In fact, I might argue the opposite. Why not have events at cemeteries? Most people only go to a cemetery to attend a funeral or maybe on anniversaries. That feels like a ritual of obligation to me. And more than that, I think people are way too easily offended. Respect comes in many different shades and in the end — quite literally — a cemetery is something like a community of people who once came from many different backgrounds, beliefs, and personalities. At any rate, a cemetery exists in time and place — it has substance and history — and it didn’t emerge ex nihilo as a sacred place. We need not pretend otherwise to be respectful.